1. Field of the Invention
The present invention relates to a device for and method of measuring blood flow. More particularly, the present invention relates to a device for and method of measuring blood flow using bio-photon emission.
2. Description of the Related Art
Cardiovascular diseases (CVDs), along with cancers, are regarded as the most life threatening illnesses to modern human beings. Among CVDs, a cerebral apoplexy, i.e., a stroke, occurs when, due to hardening of the arteries and cholesterol collected on the walls of blood vessels in the brain, the blood vessels become narrow or clogged. Thrombus may be produced in portions of a body, such as the heart and its adjacent organs, where the arteries are hardening. In addition, mental stress reduces the amount of blood that flows into the heart, thus resulting in a high probability of death from heart disease.
Generally, death from heart disease most likely occurs in patients whose coronary arteries, which send blood to the heart, narrow by 50% in at least one portion of the coronary arteries or who have already had one or more heart attacks.
An ischemic stroke can be categorized into two types, a complete ischemic stroke or a partial ischemic stroke depending on how blood circulation disorder is affected. In a case of a complete ischemic stroke, blood circulation in a portion of the brain is completely cut off, and a cerebral infarction occurs. Since a cerebral infarction makes the portion of the brain in which it occurs functionally irrecoverable, disorders due to the cerebral infarction are permanent.
A transient ischemic attack (TIA) is transient and includes local neurological symptoms due to a transient reduction of the blood supply to the brain. A TIA causes symptoms similar to a stroke, but differs from the stroke in that the TIA is only a temporary disease. In particular, a TIA may last for several minutes and then disappear. A TIA is a warning signal that a patient might have a stroke later due to dysfunctional blood circulation in the brain.
A conventional method of measuring an amount or rate of blood flow can be categorized into a method using the Doppler effect and a method using electromagnetic induction. Further, the method using the Doppler effect is classified into a method using a laser and a method using ultrasonic waves. When a laser Doppler blood flowmeter is used, the rate of blood that flows through blood vessels is measured by inserting a glass fiber into a blood vessel and irradiating a laser beam in the blood vessel. Then, the rate of blood is measured using a variation of wavelength of a reflected light. When an ultrasonic blood flowmeter is used, blood flow is measured using a variation of an ultrasonic wave that is externally applied to blood. A fundamental principle of the ultrasonic blood flowmeter is the same as that of the laser Doppler blood flowmeter. An electromagnetic blood flowmeter measures the amount or rate of blood flow by detecting an electromotive force (EMF) of blood generated after a magnetic field is applied to blood vessels.
Disadvantageously, measurement results of blood flow using the aforementioned conventional blood flowmeters are not precise because signals are affected by a stimulus to a human body or tissues inside or outside the skin. In addition, because these blood flowmeters are bulky, they are quite difficult to use, install, or transport.